(CNN) -- A compromised levee in Poplar Bluff, Missouri, failed Tuesday, forcing authorities to order more evacuations in the region.

The levee failed in at least four locations along a two-mile stretch along the Black River, City Manager Doug Bagby said.

The failure was sending floodwaters from the Black River into a populated but rural area of Butler County, sparing the city of Poplar Bluff, said the city's deputy police chief, Jeff Rolland.

Authorities were worried about another one to three inches of rain in the forecast.

It was unclear how many people might eventually be affected by the flooding, Butler County Sheriff's Detective Scott Phelps said. As of midafternoon Tuesday, several hundred homes had been evacuated in the county, he said. The breaks occurred between Poplar Bluff and the community of Qulin, about 12 miles to the southeast.

Missouri Gov. Jay Nixon said 59 water rescues were conducted and nearly 7,000 people had to be moved in Butler County. Bagby said about 1,000 of them are city residents, with more than 200 being sheltered at Black River Coliseum.

Flood levels are dropping slowly, Bagby said, and people may be able to return to their homes Wednesday afternoon if the trend continues.

"It's sunny in Poplar Bluff right now," Bagby said on Tuesday afternoon.

The city has received 15 inches of rain in the last four days, Rolland said -- five of them in just one storm Monday.

"It's just extraordinary," Rolland said.

Nixon deployed about 200 members of the Missouri National Guard to Poplar Bluff and the southeastern corner of the state for what the National Weather Service said could be record flooding. Nixon ordered troops to help with efforts to shore up levees near Poplar Bluff and other river communities, among other duties.

"A lot of people are getting very worried that they're going to see higher levels than they've ever seen before," said Aaron Luke, a Nashville resident, who visited family in the Poplar Bluff area over the weekend.

Luke left his car at an aunt's house north of Poplar Bluff when rising waters prevented him from leaving the area.

"I had to grab a rental car to get out and return to Nashville," he said, after using a boat to get across a swollen creek.

Authorities ordered residents most at risk to evacuate immediately. Other residents near the river were asked to closely monitor developments and water levels in their neighborhoods, the police department said.

Daryl Nelson helped evacuate his father and sister from the south end of the city.

"You don't know when it's going to be over and you can get back in," he told CNN affiliate KFVS. "It's better than getting everything ruined."